In most practical applications, grid welding machines are used in which the horizontal group of longitudinal wires is moved intermittently to allow welding the longitudinal wires at non-moving points of intersection of the grid to laterally fed cross wires in intervals between movements. It is a disadvantage in this respect that the entire grid and the entire device needed for its movement must be braked down and accelerated again for each of the welding phases, which produces much noise and leads to a very high energy consumption.
To avoid these disadvantages, the applicant has proposed a continuously operating welding system in its patent specification AT-B-357 005. The group of longitudinal wires is moved continuously at a constant speed in the longitudinal direction and cross wires are conveyed towards the longitudinal wires one after the other above the moving group and brought into contact with said longitudinal wires in the correct orientation and in accordance with the scaling of the cross wires, and welded to them at the points of intersection of the grid by means of electrodes and counter electrodes using the electrical resistance principle; the lower electrodes are pressed against the upper counter electrodes with the points of intersection arranged therebetween. The electrodes and counter electrodes are configured as rolls which are pivotably mounted to axles arranged transversely to the longitudinal direction and roll off each other with the points of intersection of the longitudinal wires and cross wires which are passing through; the electrodes make only sporadic contact with each other at the respective points of intersection. The duration of the welding processes is limited to a short period of sporadic contact of the rotating rolls, such that this period of time is only sufficient for complete welding at the points of intersection when the grid passes through very slowly. For the same reason, grids made of thicker wires can therefore not be produced at all using this process.
This applies likewise to the method known from the applicant's patent specification AT-B-346 668 for producing a lattice strip of intersecting groups of wires which extend in a zigzag shape relative to the longitudinal direction of the strip. Here, the groups of wires continuously pass through a welding area comprising electrodes which are moved along. Again, only low production speeds and/or wire diameters can be used due to the short period of time available for welding.